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Glacial Flooding & Disaster Risk Management Knowledge Exchange and Field Training July 11-24, 2013 in Huaraz, Peru

Sampling of  light  absorbing  particulates  on  the  glaciers  of  the   Cordillera  Blanca,  Peru   Carl  G.  Schmitt   National  Center  for  Atmospheric  Research   Aaron  Celestian,  John  All,  Melinda  Rucks,  Justin  Cave   Western  Kentucky  University   William  P.  Arnott   University  of  Nevada,  Reno   Rebecca  J.  Cole   Institute  of  Arctic  and  Alpine  Research   Abstract   Glaciers  in  tropical  regions  have  been  losing  mass  at  an  extremely  high  rate  since  the   1950s.    This  can  be  caused  by  several  factors.    The  temperature  in  tropical  regions  has  been   shown  to  be  increasing  and  is  predicted  to  continue  to  increase  due  to  global  climate   change.    Weather  patterns  may  also  change  significantly  due  to  climate  change.    A  third   factor  that  could  be  leading  to  higher  glacier  melt  rates  is  increased  dust  and  black  carbon   loads  on  the  surface  of  the  glaciers.    The  research  presented  here  investigates  this  third   factor.    During  the  dry  season  of  2011  and  2012,  the  American  Climber  Science  Program   (ACSP)  sampled  light  absorbing  particulates  on  glacier  surfaces  in  the  Cordillera  Blanca   mountain  range  in  the  Peruvian  Andes.    One  hundred  and  fifty  samples  have  been  collected   and  filtered  during  two  field  seasons  by  volunteer  climbers  working  with  scientists  in  the   field.  Glacier  snow  and  ice  was  collected  on  thirteen  peaks  throughout  the  range  at   altitudes  from  4800  to  nearly  6800  meters.  After  collection,  snow  samples  were  rapidly   melted  and  then  immediately  filtered  through  0.7  micron  quartz  fiber  filters  in  the  field.   The  particulates  captured  on  the  filters  have  been  analyzed  for  their  bulk  heat  absorption   properties.    Results  show  that  glaciers  that  are  close  to  human  population  centers  can  have   up  to  five  times  more  light  absorbing  particles  than  remote  glaciers.    Results  indicate  that   snow  age  and  altitude  all  play  a  significant  role  in  the  amount  of  contaminants.  Multiple   locations  have  been  sampled  during  both  expeditions  as  well  as  at  different  times  during   the  same  climbing  season.  The  2012  results  show  similar  trends  to  the  2011  results.     Sampling  will  continue  in  the  2013  climbing  season  with  additional  measures  to  better   quantify  the  black  carbon  amounts  directly  resulting  from  pollution.       1. Introduction Understanding  water  availability  and  how  this  availability  will  change  with  ongoing  climate   change  will  help  policy  makers  to  design  policies  supporting  local  and  regional   sustainability.    The  glaciers  of  the  Cordillera  Blanca  mountain  range  in  Northern  Peru  have  

been receding  rapidly  (Rabatel  et  al,  2013).    There  are  several  possible  factors  affecting  the   glacier  loss  in  the  tropical  Andes.    The  most  evident  is  temperature  increase  over  the  globe   caused  by  the  increase  in  greenhouse  gasses  in  the  atmosphere.    The  temperature  increase   in  the  tropics  is  estimated  to  be  approximately  0.1C  per  decade  over  the  last  70  years.    A   second  possible  factor  is  that  this  temperature  increase  has  significant  additional  impact  on   atmospheric  circulation  patterns.    Weather  patterns  may  have  shifted  causing  a  decrease  in   precipitation  in  the  region.    Seidel  et  al.  (2008)  showed  that  the  tropical  belt  is  widening   due  to  the  strengthening  of  the  Hadley  circulation  in  the  tropics.    To  date,  significant   precipitation  alterations  have  not  been  observed  in  the  tropical  Andes,  but  as  the  tropical   environment  continues  to  evolve  with  climate  change,  this  could  change.    Land  use  changes   in  the  surrounding  regions  can  also  significantly  influence  precipitation  timing  and   location.    Finally,  the  topic  of  this  study,  snow  contamination  by  the  introduction  of   increased  amounts  of  light  absorbing  particulates,  can  also  result  in  increased  melt  rates.     This  study  reports  on  recent  measurements  of  light  absorbing  materials  sampled  on  the   glaciers  of  the  Cordillera  Blanca  mountains  in  Peru.       Sources  of  black  carbon  and  dust  in  the  Cordillera  Blanca  are  numerous.    Our  emphasis  is  to   understand  the  change  in  the  anthropogenic  contribution  because  these  changes  are   important  to  understanding  human  impacts.    Contaminants  include  black  carbon  which  is  a   product  of  incomplete  combustion  of  carbon  based  fuels.    Obvious  sources  of  black  carbon   include  industry,  transportation  (especially  diesel  fuel),  and  agricultural  burning.    One   interesting  question  is  whether  or  not  there  is  a  significant  impact  in  the  Cordillera  Blanca   from  agricultural  burning  or  long-­‐range  transport  of  ash  from  forest  clearing  by  fire  in  the   Amazon  basin.    Increases  in  dust  can  be  caused  by  increased  traffic  on  dirt  roads  as  well  as   from  mining  activities.    Because  there  are  several  dirt  roads  through  the  Cordillera  Blanca   that  receive  heavy  traffic  as  well  as  several  open  pit  mines  in  the  region,  increased  dust   load  on  the  glaciers  could  be  a  significant  factor.       With  population  growth,  populations  have  adapted  to  the  natural  cycle  of  glacier  runoff.     Seasonal  water  availability  has  led  to  choices  in  agricultural  practices  as  well  as  reservoir   size  in  order  to  maintain  a  constant  supply  of  water  for  agricultural,  municipal,  and   hydroelectric  power  uses.    As  the  glacier  melt  rates  have  increased,  water  flow  rates  have   likely  increased  as  well.    In  the  future,  as  glacier  mass  continues  to  decrease,  the  semi-­‐ constant  water  contribution  from  glacier  melt  will  start  to  decrease.    Understanding  the  ice   melt  rates  will  enable  better  policy  decisions  to  be  made  to  facilitate  sustainable  water  use   in  the  future.   Pollution  and  dust  on  glaciers  has  been  shown  to  significantly  increase  ice  melt  rates   (Painter  et  al.  2012).    Glaciers  near  population  centers  are  particularly  important  to  water   supply.    In  addition  to  glacier  mass  loss  from  climate  change,  glaciers  near  population   centers  can  have  additional  melting  due  to  added  light  absorbing  pollutants  on  ice  surfaces.     This  paper  reports  on  new  measurements  of  dust  and  pollutants  on  the  glaciers  of  the   Cordillera  Blanca  mountains  in  Peru.    The  work  is  conducted  as  part  of  the  American   Climber  Science  Program  which  will  be  briefly  discussed  in  section  2.    Section  3  will  discuss   the  analysis  techniques  and  the  results.    Section  4  will  discuss  some  of  the  implications  of   the  findings  from  the  first  two  years  of  measurements.      

2. The  American  Climber  Science  Program  Expeditions:   The  American  Climber  Science  Program  (ACSP)  is  a  citizen-­‐science  program  designed  to   facilitate  research  opportunities  for  scientists  in  regions  which  are  difficult  to  access.     Scientists  and  climbers  come  together  for  expeditions  to  collect  data  for  scientific  projects   and  to  share  their  enthusiasm  for  the  mountains.    Research  expeditions  are  also  designed   to  provide  opportunities  for  non-­‐scientists  to  learn  about  scientific  practices  as  well  as  to   instruct  future  scientists  on  safety  in  mountain  regions.       During  the  dry  season  in  the  Cordillera  Blanca  region  in  2011,  the  first  ACSP  scientific   expedition  was  conducted  with  one  of  the  scientific  goal  being  the  sampling  of  black  carbon   and  dust  in  glacial  snows.    In  2011,  48  samples  were  collected  and  returned  to  the  US  for   analysis.    In  2012,  the  core  team  from  2011  along  with  a  new  group  of  volunteers  returned   to  the  Cordillera  Blanca  for  the  second  ACSP  expedition,  collecting  100  samples  for   analysis.    Samples  were  collected  from  glacial  surfaces  from  an  altitude  of  4800  meters  and   at  regular  intervals  up  to  6800  meters.    Several  locations  were  sampled  during  both   expeditions  and  multiple  samples  were  taken  from  the  walls  of  a  crevasse  on  one  occasion   to  identify  long  term  trends.   Samples  were  collected  by  scooping  snow  into  ziplock  plastic  bags.    Hands,  gloves,  or  ice   tools  were  ‘contaminated’  with  local  snow  before  sampling  to  reduce  potential   contamination  of  samples.    Approximately  1  kilogram  of  snow  was  collected  at  each  site   from  both  the  surface  (defined  as  the  top  2.5  cm)  and  the  sub-­‐surface  (deeper  than  2.5  cm)   at  each  site.    Snow  samples  were  packed  together  into  backpacks  and  returned  to   basecamp  for  processing.       In  camp,  snow  samples  were  melted  one  at  a  time  by  placing  the  ziplock  bags  into  near-­‐ boiling  water.    Once  melted,  the  melt  water  was  drawn  into  60  mL  syringes  and  pushed   slowly  through  0.7  micron  quartz  fiber  filters.    Ten  syringes  of  water  were  used  per  sample   making  a  total  of  600mL  of  water  filtered  per  sample.    Filters  were  removed  from  filter   holders  and  placed  into  airtite  coin  collection  coin  holders  and  held  in  place  with  a  thin   foam  ring.    After  each  field  session  (generally  approximately  7  days)  the  filters  were   returned  to  Huaraz  where  they  were  dried  in  the  sun,  then  stored  in  a  freezer  until  they   were  returned  to  the  US.       3.    Analysis  and  Results   The  filters  from  the  2011  and  2012  expeditions  have  been  analyzed  to  determine  the  heat   absorption  capacity  of  the  captured  particles.    Each  filter  was  suspended  above  a  constant   temperature  surface  (ice  water)  by  placing  it  on  two  crossed  threads.    An  infrared   thermometer  was  used  to  measure  the  temperature  of  the  filter.    The  ice  water  background   assured  that  the  infrared  thermometer  was  aimed  correctly.    To  determine  the  light   absorption  capacity  of  the  materials,  an  incandescent  light  was  turned  on  close  to  the  filter.     The  particulates  on  the  filter  absorbed  the  radiation  from  the  light  causing  the  filter  to  heat   up.    The  temperature  of  the  filter  was  noted  after  fifteen  seconds.    The  temperature   increase  ranges  from  10C  for  an  unused  filter,  to  40C  for  the  most  heavily  contaminated   filters.    During  analysis,  after  every  ten  filters,  two  control  filters  were  tested  to  assure  

consistency in  the  setup.    The  control  filters  included  an  unused  clean  filter  and  a  filter   darkened  with  a  sharpie  pen  which  had  higher  absorption  than  any  of  the  experimental   filters.   The  light  absorption  capacity  of  each  filter  can  now  be  compared  though  the  results  have   not  been  calibrated  in  an  absolute  sense.    Even  without  absolute  calibration,  the  relative   results  present  a  striking  picture.    Relative  results  are  compared  by  assigning  a  heat   absorption  capacity  value  of  zero  for  an  unused  filter  and  a  heat  absorption  capacity  value   of  100  for  the  filter  with  the  highest  heat  absorption  capacity  for  each  year.    As  there  was  a   minor  change  in  equipment  used  between  the  2011  and  2012  seasons,  each  year’s  data  has   been  scaled  individually.    Figure  1  shows  the  average  heat  absorption  capacity  for  each  of   the  valleys  based  on  the  filters  collected  for  the  2011  and  2012  data.    Only  filters  collected   at  altitudes  higher  than  5000  meters  were  used  in  the  comparison  in  order  to  avoid   influence  from  local  dust  sources.    Data  from  both  years  show  a  distinct  trend  with  the   northern  mountains  being  relatively  clean  compared  to  the  mountains  near  Huaraz.  

Figure  1:    Relative  heat  absorption  capacity  for  particulates  in  snow  sampled  in  the  different   valleys  or  individual  mountains  of  the  Cordillera  Blanca.    Blue  bars  represent  measurements   from  2011  and  red  represent  measurements  from  2012.    The  Santa  Cruz  and  Llanganuco   valleys  (left)  are  north  of  Huaraz  while  the  Ishinca  and  Quilcayhuanca  valleys  and   Vallunaraju  (right)  are  near  Huaraz  and  therefore  more  polluted.       There  are  several  possible  factors  that  could  lead  to  the  observed  trends.    Higher  levels  of   pollution  from  the  town  of  Huaraz  as  well  as  the  higher  abundance  of  dirt  roads  could   contribute  significantly.    Mining  activities  are  also  more  significant  at  the  Southern  end  of   the  range.    It  should  be  noted  that  a  storm  moved  through  the  region  during  the  2011   season  immediately  before  climber-­‐scientists  sampled  a  subset  of  the  mountains.    Even   though  the  entire  range  received  fresh  snow  and  the  snow  was  sampled  at  several  locations   in  the  north  and  south  of  the  range  within  2-­‐3  days  of  the  storm,  the  trends  shown  in  figure   1  were  still  present.    Although  the  storm  system  may  have  had  a  significant  load  of  dust,  the   snow  may  still  have  been  influenced  by  local  sources.      

4.  Implications  and  future  work   Airborne  and  snowborne  particulates  can  contaminate  the  surface  of  glaciers  leading  to   reduced  albedo  and  increased  melting  rates.    Our  measurements  indicate  that,  in  the   Cordillera  Blanca,  particulates  are  significantly  more  abundant  in  the  mountains  near  to   Huaraz,  the  largest  local  population  center.    The  implications  of  this  are  significant,  as  melt   water  is  an  important  natural  resource  for  the  region  for  agriculture,  drinking  water,  and   hydroelectric  power.    It  is  well  known  that  tropical  glaciers  are  melting  rapidly.    With   added  pollutants  from  population  centers,  the  glaciers  nearby  could  be  at  significantly   greater  risk  of  melting  rapidly.    Local  and  regional  planners  need  to  be  aware  that  glacier   melt  rates  for  highly  used  water  sources  could  be  melting  at  a  significantly  faster  rate  than   more  remote  glaciers,  potentially  putting  their  water  sources  at  even  greater  risk.   The  ACSP  is  continuing  to  sample  snow  in  the  Cordillera  Blanca  in  a  2013  expedition.    With   three  years  of  data  it  will  be  possible  to  look  at  changes  with  respect  to  time.    Additional   sampling  protocols  are  being  implemented  to  better  categorize  the  different  types  of   pollutants  on  the  glaciers  in  order  to  better  understand  the  sources.    A  Droplet   Measurement  Technology  (DMT)  Soot  Photometer  –  2  (SP2)  will  be  used  to  analyze   samples  from  the  2013  for  black  carbon  content  for  pollution  size  particles.    With  this   information  and  co-­‐located  filter  samples,  it  will  be  possible  to  use  an  integrated  sandwich   spectrometer  setup  (Grenfell,  2011)  to  separate  black  carbon  from  dust  in  all  previous   samples.    These  future  results  will  enable  environmental  decision  makers  to  better   understand  the  challenges  facing  their  glaciers.    Possible  mitigation  activities  include   vehicle  emission  controls,  agricultural  burning  limitations,  or  dust  mitigation  for  dirt  roads   or  mining  operations.   References   Grenfell,  T.  C.,  S.  J.  Doherty,  A.  D.  Clarke,  and  S.  G.  Warren,  2011:  Light  absorption  from   particulate  impurities  in  snow  and  ice  determined  by  spectrophotometric  analysis   of  filters,  Applied  Optics,  50,  1-­‐12.   Painter,  T.  H.,  S.  M.  Skiles,  J.  S.  Deems,  A.  C.  Bryant,  and  C.  C.  Landry,  2012:  Dust  radiative   forcing  in  snow  of  the  upper  Colorado  river  basin:  1.  A  6  year  record  of  energy   balance,  radiation,  and  dust  concentrations.  Water  Resources  Research,  48,   doi:10.1029/2012WR011985,2012.   Rabatel,  A.,  B.  Francou,  A.  Soruco,  J.  Gomez,  B.  Caceres,  J.  L.  Cabellos,  R.  Basantes,  M.  Vuille,  J.   E.  Sicart,  C.  Huggel,  M.  Scheel,  Y.  Lejeune,  Y.  Arnaud,  M.  Collet,  T.  Condom,  G.  Consoli,   V.  Favier,  V.  Jomelli,  R.  Galarraga,  P.  Ginot,  L.  Maisincho,  J.  Mendoza,  M.  Menegoz,  E.   Ramirez,  P.  Ribstein,  W.  Suarez,  M.  Villacis,  and  P.  Wagnon,  2013:  Current  state  of   glaciers  in  the  tropical  Andes:  a  multi-­‐century  perspective  on  glacier  evolution  and   climate  change.    The  Cryosphere,  7,  81-­‐102.   Seidel,  D.  J.,  Q.  Fu,  W.  J.  Randel,  T.  J.  Reichler,  2008:  Widening  of  the  tropical  belt  in  a   changing  climate.  Nature  Geosciences,  1,  21-­‐24.    

Carl Schmitt: Sampling of light absorbing particulates on glaciers of Cordillera Blanca, Peru  

Glaciers in tropical regions have been losing mass at an extremely high rate since the 1950s. This can be caused by several factors. The t...